WASHINGTON, April 21 (Reuters) – Contracts to purchase previously owned U.S. homes increased more than expected in March, but higher mortgage rates and ?tight inventory remained constraints for the housing market.

The ?pending home sales index rose 1.5% last month to 73.7, the National Association of Realtors said on Tuesday. Economists polled by Reuters had forecast contracts, which ?become sales after a month or two, increasing 0.5%.